AB0925 DERMATOMYOSITIS AS A PARANEOPLASTIC SYNDROME OF TONSILLAR CARCINOMA: FIRST REPORTED CASE IN THE UK
Authors: A. Younas, R. Asif, R. Davies
Journal: Annals of the Rheumatic Diseases (2023)

<h3>Background</h3> Dermatomyositis (DM) has a strong association with Malignancy, with one study showing risk up to five times that of the general population and is the leading cause of death [1]. Occult cancer can result in resistant disease, and early diagnosis can improve patient outcomes. We report a case of occult tonsillar cancer associated with severe DM. <h3>Objectives</h3> Our report sought to report the presentation of occult tonsillar cancer with severe dermatomyositis. <h3>Methods</h3> A 60-year-old usually fit and well gentleman presented with a 4-month history of progressive proximal muscle weakness of upper and lower limbs and a characteristic erythematous rash suggestive of DM. Investigations showed a CK of 6813 U/L typical myositis changes on MRI and positive myositis specific Anti-NXP ab. An initial malignancy screen, including CT TAP, was negative for underlying malignancy. He was commenced on oral Prednisolone at 1mg/kg and was discharged with urgent rheumatology follow-up. However, he was admitted a week later with severe dysphagia and ongoing muscle weakness. An urgent OGD excluded a structural upper GI lesion, and Nasogastric feeding was commenced. He was administered IV methyl Pred 500 mg over three days along with IVIG (2g/kg) but failed to respond with ongoing muscle weakness and dysphagia. A subsequent PET scan showed a right tonsillar mass, later confirmed as tonsillar cancer on biopsy. Following this, the ENT team proceeded with robotic surgery and radical surgical resection of tonsillar cancer. We repeated IVIG every four weeks along with IV Methyl pred 50 mg OD and a PEG tube inserted to meet his nutritional needs. Gradually he started to show signs of improvement with improved mobility, muscle strength, and normal CK levels. He received six cycles of IVIG, and azathioprine was commenced with the weaning of prednisolone to 10 mg after discharge. 6 months after the initial presentation, he mobilized independently with improved swallowing to liquids and a soft diet. <h3>Results</h3> Head and neck cancers are rarely associated with Dermatomyositis, with tonsillar cancer extremely rare. To our knowledge, this is the first reported case of occult tonsillar cancer associated with treatment-resistant DM. Detecting occult cancer can be difficult, especially in cases where the DM symptoms precede cancer diagnosis. The usual first-line cancer screening in inflammatory myopathies includes CT TAP, which can miss a malignancy of the head and neck region. Current evidence does not show a definite benefit of PET scanning over conventional CT for cancer identification [2]. But PET scanning can be very useful in selected patients with a high index of clinical suspicion. Recently published BSR guidelines recommend considering PET scanning for cancer screening [3]. <h3>Conclusion</h3> Increased vigilance is required to look for occult cancer, including head and neck cancers, especially in patients with treatment-resistant DM. PET scanning can potentially aid in early cancer diagnosis and guide definitive treatment. <h3>References</h3> [1]Qiang JK, Kim WB, Baibergenova A, Alhusayen R. Risk of Malignancy in Dermatomyositis and Polymyositis. J Cutan Med Surg. 2017;21(2):131-136. doi:10.1177/1203475416665601 [2]Maliha PG, Hudson M, Abikhzer G, Singerman J, Probst S. 18F-FDG PET/CT versus conventional investigations for cancer screening in autoimmune inflammatory myopathy in the era of novel myopathy classifications. Nucl Med Commun. 2019;40(4):377-382. doi:10.1097/MNM.0000000000000981 [3]Oldroyd AGS, Lilleker JB, Amin T, et al. British Society for Rheumatology guideline on management of paediatric, adolescent and adult patients with idiopathic inflammatory myopathy. Rheumatology (Oxford). 2022;61(5):1760-1768. doi:10.1093/rheumatology/keac115 <h3>Acknowledgements:</h3> NIL. <h3>Disclosure of Interests</h3> None Declared.